1. Field of the Invention
The field of the invention relates to medical imaging, specifically to the Processing anatomic images acquired in volume.
2. Description of Related Art
Whether one uses tomographic radiography (CT scanner) or other techniques for the acquisition of images in volume, the acquisition of images may from the neck to the feet).
Thus, according to the parts of the anatomy or organs to be examined, the processing of images that is applied is often varied, with the performance of each processing being optimized for the images where only the part of the anatomy to be examined is present.
Likewise, it is desirable for the practitioner to be able to have access immediately to images corresponding exactly to the part of the anatomy that he is to examine, even if the acquisition is done by covering an anatomic zone that is larger than the one on which he would like to work.
That is why it appeared desirable to be able to segment and to automatically identify the images of different parts of the anatomy and of different organs that were the object of the imaging.
It has already been proposed in U.S. Pat. No. 1,177,453 for a method of 3D analysis of images according to which the images are partitioned into different sub-volumes in particular to allow further optimized processing.
However, the technique described in this document concerns principally the analysis of the upper part of the body.
The invention proposes processing to allow the partitioning of the principal atomic parts of a person: head, neck, thorax, lungs, heart, abdomen, lower members.
The invention also proposes processing to allow the isolation of views of certain organs of the anatomy: heart, lung, aortic arch, etc.
More particularly, a method is proposed that involves processing anatomic images acquired in volume by a system of medical imaging, to partition the images into sub-volumes corresponding to different parts of the anatomy identified on said images, wherein to effect this partitioning one processes the acquired images by identifying those on which the lungs appear, and if the lungs are identified, the upper and lower slices are determined, delimiting them according to the axis of the anatomy on which the images have been acquired, and a distance processing is applied to these images, corresponding to the anatomic zones respectively above and below these two slices.
Thus, is proposed to use the lungs as a physical reference point to partition the images. If they are not contained in the examination, their absence from the images already gives interesting information on what is possibly not present (e.g., the heart and the thorax), and thus on what it is not necessary to try to detect.
To identify the lungs on the images, one in particular applies processing designed to remove the air in the trachea on the images, according to which:                the closely related components of air that appear on the acquired images are determined,        an average 3D excentricity is determined in them,        a threshold the average 3D eccentricity so calculated is compared to preserve only these closely related components whose 3D eccentricity is less than a first threshold, and whose length on the z axis is greater than a second threshold,        the components thus isolated are then subtracted from the images.        
Likewise, when the lungs are detected, one applies processing to identify and to partition the images corresponding to the heart.
However, one first compares the length of the anatomy appearing on the images to a given threshold, the said processing being designed to identify and partition the images corresponding to the heart being applied only when said length is greater than the said threshold.
In particular, to determine the slice corresponding to the upper limit of the heart, at least three axial slices are determined on which one identifies the ascending aorta and the descending aorta.
Likewise, when the lungs are detected, an axial surface profile occupied by the voxels on the slices below the lower slice limit of the lungs is determined, and a determination is made of the presence of the abdomen and of various parts of the legs in analyzing this profile.
When the lungs are not detected, the length of the anatomy that is the object of the acquisition of the images is compared to a threshold; if this length is greater than the said threshold, an axial profile of the surface occupied by the voxels on the slices is determined, and a determination is made of the presence of the abdomen and various parts of the legs in analyzing this profile.
When the analysis of the profile does not allow determination of the presence of the abdomen and of various parts of the legs, an axial profile of the air appearing on the slices is determined, and an analysis of this profile is made to deduce from it information on the zone of the head or neck present on the images.
Moreover, when the lungs are detected, an axial profile of the air appearing on the slices above the upper slice limit of the lungs is determined; an analysis of this profile is made to deduce from it information on the zone of the head or the neck present on the images.
In particular, a comparison is made in advance to a given threshold the length of anatomy above the upper slice limit of the lungs; the determination of the axial profile of the air is applied only when the said length is greater than the said threshold.
When the lungs are not detected, the length of the anatomy that is the object of the acquisition of the images is compared to a threshold; if this length is less than the said threshold, an axial profile of the air appearing on the slices is determined, and an analysis this profile is made to deduce from it information on the zone of the head or the neck present on the images.
In addition, and independently of the procedure presented below, the invention also involves a procedure for the processing of images acquired in volume by a system of medical imaging, wherein:                the axial slices perpendicular to the axis of the anatomy are reviewed to identify an axial slice corresponding to an upper limit of the heart,        on this slice two closely related components corresponding to the ascending aorta and the descending aorta are determined,        the components closely related in volume that correspond to the closely related components are determined,        the said components closely related in volume are combined,        the centers of the closely related components that correspond to it on several axial slices are determined on the component closely related in volume thus obtained,        a plan to optimize the distance with relation to the clouds of points made up by the various centers is determined.        
Embodiments of the invention propose as well a system of medical imaging means for acquiring images of anatomy in volume and the means for processing these images appropriate to partitioning the images into sub-volumes corresponding to different parts of the anatomy identified on the said images, wherein said averages are composed of averages suitable for applying processing to a method of the type presented below.
It also proposes a program stored on means for being read by a computer, the program comprising data and/or instructions for implementing such a method.